Direct synthesis of polyamides by using crystallization during polymerization

Kentaro Kobayashi, Shinichi Yamazaki, Kunio Kimura

Research output: Contribution to conferencePaperpeer-review


Direct polycondensations of isophthalic acid (IPA) and p-phenylenediamine (PPDA) were carried out by means of reaction-induced crystallization of oligomers. Poly(p-phenylene isophthalamide) (PPIA) plate-like crystals were obtained in good yield. The crystals exhibiting clear habits possessed high crystallinity. PPDA / IPA = 1.4 - 1.5 gave the highest intrinsic viscosity ([η]) of 0.37 dl/g. The yield and [η] of the polymers and the dissolved oligomers were measured in the course of the polymerization in order to examine polycondenastion feature. [η] of the polymers was increased even after the polymer yield was leveled off. On the other hand, [η] of the dissolved oligomers was constant through the polymerization. From these results, it was concluded that the polycondensation of IPA and PPDA proceeded as follows. When the molecular weight of oligomers exceeded the critical value, they were crystallized to form crystals. Solid-state polycondensation subsequently occurred in the crystals. Finally, PPIA were obtained as a form of crystals.

Original languageEnglish
Number of pages1
Publication statusPublished - Dec 1 2005
Event54th SPSJ Annual Meeting 2005 - Yokohama, Japan
Duration: May 25 2005May 27 2005


Other54th SPSJ Annual Meeting 2005


  • Aromatic Polyamide
  • Crystallization
  • Direct Polycondensation
  • Oligomer
  • Poly(p-phenylene isophthalamide)

ASJC Scopus subject areas

  • Engineering(all)


Dive into the research topics of 'Direct synthesis of polyamides by using crystallization during polymerization'. Together they form a unique fingerprint.

Cite this